The use of a new carboranylamidophosphite ligand in the asymmetric Rh-catalyzed hydrogenation of α- and β-dehydroamino acid derivatives

New chiral carboranylamidophosphite ligand was synthesized and tested in the Rh-catalyzed asymmetric hydrogenation of alpha- and beta-dehydroamino acid derivatives (up to 93% ee). The catalytic performance is affected greatly by temperature and the nature of solvents. Importantly, we have shown that in the hydrogenation of the beta-dehydroamino acid derivatives the use of acidic 1.1,1,3,3,3-hexafluoro-2-propanol led to a significant increase in the enantioselectivity, compared to isopropyl alcohol. (c) 2011 Elsevier Ltd. All rights reserved.